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%
%    Hm22.m  -  B-H interpolation routine
%
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function y = Hx(Bx)
% B-H values that follow are valid for M-22, 26 ga. ESS
B=[0 0.4 0.8 2 8 9.2 11 12.5 13.8 15.2 16.5 18 19 19.6 ...
      19.8 20 20.4 20.6 21.7 28]*6.45e3;       % Lines/sq.in.
H=[0 0.18 0.26 0.38 1.4 1.8 3 5 9.5 28 70 160 260 370 ...
      420 520 825 1000 2000 8000]*2.021;  % A-t/in.
% Activate to plot B-H curve
% m=20; plot(H(1:m),B(1:m)); grid; pause; % Linear plot
% m=20; semilogx(H(2:m),B(2:m));grid; pause; % Semilog plot
n=length(B); k=0;
if Bx==0; k=-1; y=0; end
if Bx<0; k=-1; y=0; disp('WARNING - Bx < 0, Hx = 0 returned'); end
if Bx>B(n); y=H(n); k=-1; disp('CAUTION - Beyond B-H curve'); end
for i=1:n
if k==0 & (Bx-B(i))<=0; k=i; break; end
end
if k>0;
y=H(k-1)+(Bx-B(k-1))/(B(k)-B(k-1))*(H(k)-H(k-1));
else;
end